Semi-automatic firearms, such as AR-15 type rifles, and shotguns, are designed to fire a round of ammunition, such as a cartridge or shot shell, in response to each squeeze of the trigger of the firearm, and thereafter automatically load the next shell or cartridge from the firearm magazine into the chamber of the firearm. During firing, the primer of the round of ammunition ignites the propellant inside the round, producing an expanding column of high pressure gases within the chamber and barrel of the firearm. The force of this expanding gas propels the bullet/shot of the cartridge or shell down the barrel.
In semi-automatic rifles and shotguns, a portion of the expanding gases typically are directed through a duct or port that interconnects the barrel of the firearm to a piston assembly that generally houses an axially moveable piston. This piston assembly further typically includes a gas block that connects the piston assembly to the barrel, and through which the explosive gases pass. There is a need for an efficient gas block securing and release system.